Reciprocating electric motor.



PATENTED APR. 19, 1904..

APPLIOATION FILED MAR.16, 1903.

N0 MODEL.

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NW NN. Q L1 1% .C .C QM GC@ .N H 1|! IIMII w NWI im. imm .HHN l| EPatented April 19, 1904.

ADOLPH F. CHRISTMAS, OF PITTSBURG, PENNSYIVANIA, ASSIGNOR AOF TWO-THIRDSTO` FRANK R. MCFEA'ITERS,

PENNSYLVANIA.

i OF WILKINSBURG,

RECIPROCATING ELEQTFuc -M01-on.

SPECIFICATION forming part of Lettersl Patent No. 757,991, dated Aiprl19,1904.

l Application filed m8101116, 1903. Serial N0. 148,009. (N0 model.)

lo all whom, it may concern,.-

lBe it known that I, AnoLPH F. OHRIs'rMAs,

a resident of Pittsburg, in the county of Alleghen y and State ofPennsylvania, have invented a new and useful Improvement inReciprocating Electric Motors; and I do hereby declarethe following tobe a full, clear, and eX- act description thereof.

My invention relates to reciprocating electric motors; and its object isto provide a motor of this' type adapted for use with alternatingcurrents and so constructed and arranged that sparking on the breakingof the circuit is very largely reduced.

A further object of my invention' is to provide simple and efiicientmeans for cooling reciprocating electric motors, and especially such asoperate at high speeds.

One difficulty in adapting reciprocating electric motors to alternatingcurrents has been due to the extensive sparking that takes place at theterminals when the circuit is broken. i A further diiiiculty has arisenfrom the fact that such motors usually heat excess ively, thus cuttingdown the current passing through the magnet-coils and making itnecessary to frequently stop the same in order to permit them to cool.

The objectlof my invention is to provide a reciprocating electric motoradapted for use with alternating currents wherein both, and especiallythe first, of the above defects in prior motors are overcome.

'lo this end the invention consists, primarily, in so arranging theparts of the motor that the current through the coil is interrupted atthe moment of greatest self-induction, thus reducing the spark at theterminals to a minimum.

'lhe invention also consists in providing the magnet coil or coils ofthe motor with ventilating duets or passages and connecting to thereciprocating armature a piston moving in a cylinder and so arrangedwith reference toy the ventilating-ducts as to circulate air throughsaid Ventilating-duets, thus keeping the motor cool.

1n the accompanying drawings, Figurel is a longitudinal section throughmy improved motor, showing the same applied to a reciprocating hammer;and Fig. 2 is a detail view showing the circuit broken.

In the drawings the motor is shown applied to.. an ordinaryreciprocating hammer; but it will be understood that this is forpurposes of illustration merely, as the motor can be applied to any usewhere a reciprocating electric motor is desirable or advantageous. Themotor itself comprises the electromagnet-eoil l, which preferably ishollow, as shown, and having coperating therewith the armature or core2. The arrangement isfsueh that normally the core 2 is partially drawnout of the coil, so that the energization of said coil will draw thecore into the same in the well-understood mode of operation ofelectromagnets. c

It is this inward movement of the core that performs the work, and whenapplied to a hammer such as shown the tool-shank 3 is placed in suchposition that it `will be struck by the end of the core 2 at or near thelimit of the inward movement of the latter. `Suitable means will beprovided for withdrawing the core, the means shown in the drawingscomprising a spiral spring 4, interposed between the end of themagnet-coil 1 and apiston or head 5, formed on the outer end of thecore. As long as the magnet is not energized the spring 4L will hold thecore in the position shown in Fig. l; but as soon as current is suppliedto the coil 1 the core 2 will be drawn inwardly and strike thetool-shank 3 a sharp blow. yBefore the core 2 can be again withdrawn itis necessary to break the circuit to the coil l in order to denergizethe same, and it is in the arrangement for doing this that my inventionprincipally consists.

It is Well known that a current circulating around an iron core has amuch greater seltinduction than one without an iron core, this being dueto the fact that the former has a `more intense magnetic iield throughsaid iron core.

current passing through the coil 1 will be Consequently theself-induction of the greatest when the core 2 is fully drawn into saidcoil-that is, when the iron mass composed of thecore 2 and other partsis posi- -tioned symmetrically with reference to the coil dr when theair-gap between the movable core and the stationary iron parts isreduced to zero--and it is also then that the current practically ceasesto do any work. At the moment of greatest self-induction the currentpassing through the coil is correspondingly decreased in strength, andconsequently if the circuit be broken at that moment the spark at thecircuit-terminals will be reduced to the minimum. My motor is soarranged that the circuit is broken at the moment of greatestself-induction. Various arrangements may be employed for accomplishingthis purpose, and in the drawings 1 have shown one arrangement thereforwhich is simple and ettieient Ars shown, one of the circuit-wires,

such asV 6, has placed therein suitable terminals 7 and 8, which areshown as spring-iingers so arranged that normally they will springapart, as shown in Fig. 2, to 'keep the circuit open. ln suitablejuxtaposition with reference to the terminal 8 is pivoted a closing-arm9, which when brought to the position shown in llig. 1 crowds thespring-linger 8 into contact with the finger 7 to close the circuit.,but which when brought to the inclined position shown in Fig. 2 permitsthe said terminals tospring apart, thus breaking i the circuit.

the moment when said core contacts with the hammer-shank. Consequently 1attach to the core 2 an extension 10, having thereon two shoulders orcollars 11 'and 12. The collar 11 is at the outer end of said extensionand in such a position that when the core 2 has almost reached thetool-shank 3 said collar will contact with the arm 9, and by the furtherinward movement of the core said collar will draw the arm 9 to thevinclined position shown in Fig. 2, thus permitting the terminals 7 and 8to break the circuit,and this will occur at the moment when the core 2practically touches the tool-shank 8 or other stationary part of themagnet, and consequently at the moment of greatest self-induction ofsaid electromagnet. This immediately denergizes the magnet, and thespring a retracts the core 2, and in its outward movement the collar 12comes against the circuit-closing arm 9 and moves it back -to theposition shown in Fig. 1, thus again closing the circuit, so that saidcore will again be immediately drawn into the coil. lin this manner acontinuous and very rapid reciprocation of the core 2 is obtained; butthe netism across the base of the coil.

sparking at the terminals 7 and 8 is reduced to a minimum. A suitablecircuit-closer, such as the button 13, operating in conjunction withterminals 14, will be employed for placing the motor in operation. Anyother circuit-closer, however, would serve this purpose equally as well.

At each end of the magnet is an iron mass i represented by the castings15 and 16, formi ing a part of the motor-casing, and the coil 1 isprovided with an outer casing 17 and inner tube 18, both of which are ofbrass or other non-magnetizable metal and provided with slots, thusforming effective magnetic shields and preventing leakage of the linesof mag- As a result the lines of force must pass from one iron end 15 tothe other iron end 16 and practically axially of' the magnet-coil, thusgiving the maximum energy acting to draw the core into the coil.

In order to keep the motor cool, I provide the coil thereof with aseries of passages or ducts 19. 'llhe outer end or' these ductscommunicate with the atmosphere through ports 20, and the inner endthereof communicate and thehead 5 on the core 2 is practically a` pistonmoving in said cylinder. As a consequenee when the spring 4 moves thccore 2 outwardly the piston 5 will draw air through the ducts 19 intothe chamber 21. and when said core 2 moves inwardly on the energizationof the magnet said piston forces the air in the chamber 21 through theducts 19 into the atmosphere. As a consequence during the reciprocationof the core 2 air is circulated through the ducts 19, thus thoroughlyventilating the same and preventing excessive heating. By providingsimple valves the piston 5 may be made to circulate the air always inone direction, and in actual use this arrangement is preferred to theone shown in the drawings; but the latter was selected for illustrationby reason of its simplicity.

The operation of my motor will bc readily understood from the foregoingdescription. rlhe motor will be placed in any convenient circuitsupplied with an alternating current from any suitable source of power,such as the alternating generator 25. As long as the circuit-terminals14 are kept' closed the core 2 will automatically reciprocate back andforth., being drawn into the magnet-coil by the energization of thelatter and withdrawntherefrom by the spring 4 when the circuit throughthc coil is broken by the head 11' on the core extension coming intocontact with the circuitbreaker 9. This. as above explained, occurs katthe moment of greatest self-induction, and

as a consequence the sparking at the terminals 1s largely reduced.Furthermore, the circuitbreaking means 1s 1n no way dependent onnon-synchronous means for breaking said circuit at themoment of greatest'self-induction of the current. A

2. A reciprocating electric motor adapted for alternating currentscomprising a magnetcoil, a core therefor, a circuit for saidcoil, andnon-synchronous means for breaking said circuit at the moment ofgreatest self-induction of the coil.

3. A reciprocating electric motor adapted for alternating currentscomprising a magnetcoil, a core therefor, a circuit for said coil, andnon-synchronous means actuated by the core for breaking said circuitwhen said core has reached such position in the coil that the iron massis symmetrically arranged with reference to said coil.

4. A reciprocating electric motor adapted for alternating currentscomprising a single magnet-coil, a core therefor, a circuit for saidcoil', a circuit-breaker in said circuit, and a shoulder on said corearranged to contact with said circuit-breaker and open the circuit whenthe core contacts with a stationary part of the motor.y l

5. A reciprocating electric motor adapted for alternating currentscomprising a magnetcoil, a reciprocating armature coperating therewith,a circuit for said coil, non-synchronous means for breaking the circuitat the moment of greatest self-induction of the current, and mechanicalmeans for withdrawing said armature.- y

- 6. A reciprocating electric motor adapted for alternating currentscomprising a magnetcoil, a core therefor, a circuit for said coil,non-synchronous means forbreakingsaid circuit when the core contactswith a metallic l portion of the device, and a spring for Withdrawingsaid core.

7. A reciprocating electric motor adapted for alternating currentscomprising a single magnet-coil, a core' therefor, a circuit for saidcoil, a spring for withdrawing said core, acircuit-breaker, and means onsaid core for actuating said circuit-breaker when said core is fullydrawn into said coil and for making said circuit when the core reachesthe limit of its outward movement.

8. A reciprocating Velectric motor adapted for alternating currentscomprising a single magnet-coil, a core therefor, a circuit for said fcoil, a spring for'withdrawing said core, terminals in said circuitadaptedl normally to open, aA circuit-closing finger arranged to closesaid terminals, and means carried by said core and arranged'to engagesaid finger and alternately cause the same to open and close said Iterminals. x

9. A reciprocating electric motor adapted 4for alternating currentscomprising a magnetcoil, a casing therefor provided with a cylindricalextension at one end, a reciprocating armature coperating with saidcoil, ventilating ducts or passages through said magnetcoil, and apiston carried by said .armature and working in said casing extensionand arranged to cause a circulation of air through said ducts. v

10. A -reciprocating-electric motor adapted for alternating currentscomprising a magnetcoil provided with Ventilating-ducts, acasi-ngtherefor provided with a cylindrical extension at one end, a core for`said coil, a spring for retracting said core, a piston carried by saidcore and workingin said casing extension and arranged to cause acirculation of` air through said ducts, and a circuit-breaker arrangedto break the circuit when said core is fully drawn into said coil l1. A.reciprocating electric motor adapted foralternating currents comprisinga magnetcoil, a sleeve'of non-magnetizable metal for said coil, an ironmass at each end of said coil, a core for said coil, and means forbreaking the circuit to said coil.

ln testimony whereof I, the said ADOLPH F. CHRISTMAS, have hereunto setmy hand.

AnoLPH F. CHRISTMAS.

Witnesses:

MARGARET C. KEEBLE, G. C. RAYMOND.

